Browntail moth outbreaks expected statewide this year

As spring slowly moves its way into Maine, data is indicating that large parts of the midcoast and southern central parts of the state are likely to experience another tough year with the browntail moth. Maine Forest Service’s (MFS) aerial survey in fall 2018 showed over 126,000 acres impacted — double what was reported two years earlier.

The tell-tale winter webs of the browntail moth caterpillars have been spotted at the tops of some trees in Old Town, Orono and Bangor, supporting predictions by MFS and University of Maine entomologist Eleanor Groden that the invasive insect problem is spreading throughout the state.

This pest, which defoliates native oaks, cherries and hawthornes, as well as apple, crabapple and several other deciduous trees, is also a serious public health nuisance. The browntail moth caterpillars have barbed toxic (uriticating) hairs that cause severe dermatitis in most people who are exposed, and can cause respiratory issues for particularly sensitive individuals.

At UMaine, Groden and her students continue to work with MFS and other collaborators to research the dynamics of the current outbreak and potential management strategies for this pest. Their newest research project focuses on the structure of the winter webs. Working with researchers Barbara Cole and Ray Fort, and Ph.D. student Hyeweon Hwang, all in the UMaine Department of Chemistry, Groden’s team is exploring multiple life stages of the browntail moth in order to identify the weak links that may help us manage this expanding menace.

More information about Groden’s research, including community outreach, is online.

Contact: Ellie Groden, 581.2984,; Margaret Nagle, 581.3745